INVESTIGATION OF AUTO-IGNITION OF HEPTANE-CNG MIXTURE IN HCCI ENGINE. Firmansyah. Universiti Teknologi PETRONAS

Transcription

1 INVESTIGATION OF AUTO-IGNITION OF HEPTANE-CNG MIXTURE IN HCCI ENGINE Firmansyah Universiti Teknologi PETRONAS

2 OUTLINE INTRODUCTION OBJECTIVES METHODOLOGY RESULTS and DISCUSSIONS CONCLUSIONS

3 HCCI DUALFUELCONCEPT Fuels has the most significant contribution in HCCI combustion behavior.[1-8] Octane number Cetane number Autoignition temperature Combining fuels will increase the operating range of HCCI.[3-8] Dual fuel application has significant contribution in reducing the exhaust emission and improving the control of HCCI combustion.[1-2] Further understanding on the combustion process of dual fuel concept will increase the potential of dual fuel in HCCI application.

4 OBJECTIVE The current study focuses on the analysis of combustion process of dual fuel, heptane and CNG.

5 Experimental Investigated parameters: Mixture percentages, 0-100% Heptane/CNG Lambda, 0.8,1,1.2 and 2 Injection gaps, 0 and 20 ms Fuels Injection pressure Injector delivery rate (g/s) Gasoline 3 bar 4.6 CNG 7.5 bar 7.2 Heptane and CNG was injected sequentially CNG 800 C Heater temperature Heptane

6 RESULTS and DISCUSSIONS

7 Combustion Properties Heptane percentage increases Figure 3. Effect of injection gap in the combustion of heptane-cng mixtures at lambda (a) 0.8, (b) 1

8 Combustion Properties 20 ms injection gap 0 msinjection gap Figure 3. Effect of injection gap in the combustion of heptane-cng mixtures at lambda (c) 1.2 and (d) 2.

9 Detailed Combustion Properties for 70/30 Heptane/CNG Figure 4. Pressure rise rate, pressure profile and mass fraction burned at 70/30 Heptane/CNG, lambda 1 for 0 and 20 msinjection gaps

10 Detailed Combustion Properties for 70/30 Heptane/CNG Laminar Flame for 0 msinj.gap Turbulent flame for 20 ms inj.gap is detected for all time Distributed flame increase the combustion speed Flame propagation Highly stratified mixture Distributed Flame + Cool Flame Homogeneous mixture Homogeneous and stratified mixture Cool Flame

11 CONCLUSIONS From the results, it shows that mixture composition is highly determining aspects in the auto-ignition properties of the mixture as well as the properties of each constituent, fuel with lower octane number is used to be the igniter for the higher octane number fuels. Furthermore, the homogeneity level of the mixture could affect the behavior of the dual fuel combustion of where homogeneous mixture could produce distributed flame in contrary with stratified mixture that produce propagated flame. Theinjectiongapbetweenthetwofuelswillaffectthelevelofhomogeneity in the mixture. 20ms injection gap produce better combustion compared to 0ms injection gap for most of mixture compositions.

12 REFERENCES 1. Onishi. S., Jo. S.H., Shoda. K., Jo. P.D., Kato. S. Active thermo-atmosphere combustion (ATAC) a new combustion process for internal combustion engines. SAE paper No Noguchi. M., Tanaka. Y., Takeuchi. Y. A Study on gasoline engine combustion by observatioof intermiediated reactive product during combustion. SAE paper No Herold. R.E., Krasselt. J.M., Foster. D.E., Ghandhi. J.B., Reuss.D.L., Najt. P.M, Investigation into the effects of thermal and compositional stratification on HCCI combustion-part II: optical engine results. SAE Yao. M., Zheng. Z, A numerical investigation on effects if charge stratification on HCCI combustion. SAE Berntsson. A.W., Denbratt. I.G, HCCI combustion using charge combustion control. SAE Kwon. O.S., Jeong. D.W., Lim. O.T., Lida. N, The research about thermal stratification effect on pressure rise rate in supercharged HCCI engine based on numerical analysis. SAE / Yang, Y., et al. Partial Fuel Stratification to Control HCCI Heat Release Rates: Fuel Composition and Other Factors Affecting Pre-Ignition Reactions of Two-Stage Ignition Fuels. in SAE 2011 World Congress Detroit, Michigan, USA: SAE International. 8. Ranzi, E., Gaffuri, P., Faravelli, T. A Wide Range Modeling Study of n-heptane Oxidation. Combustion and Flame Pp: Curran. H. J., Gaffuri. P., Pitz. W. J., Westbrook. C. K. A ComprehensiceModeling Study of n-heptane Oxidation. Combustion and Flame Pp: Davidson. D.F., Gauthier B.M., Hanson. H.K. Shock tube ignition measurements of iso-octane/air and toluene/air at high pressures. Proceeding of the Combustion Institute pp: Jia. M., Xie. M. A Chemical Kinetics Model of Iso-Octane oxidation for HCCI engines. Fuel pp:

13 Thank You